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Biomedical subjects

A Ebihara

Publications and source records attributed to A Ebihara.

At least 145 records · Page 8Linked to original sources
PubMed1987

Diuretic and uricosuric effects of traxanox sodium in healthy subjects. Single dose study.

A new compound, 9-chloro-5-oxo-7-(1H-tetrazol-5-yl)-5H-[1]-benzopyrano[2,3- b]pyridine sodium salt pentahydrate (traxanox sodium, Y-12141) has been shown to exert uricosuric effect in animal experiments. This study was performed to investigate the pharmacokinetics and pharmacological effects of this compound in healthy subjects by double-blind, cross-over comparison with placebo. The urine volume and urinary electrolytes increased significantly after single oral doses of 120 and 360 mg. Urinary excretion of uric acid tended to increase and serum uric acid decreased significantly. Traxanox sodium did not induce any significant change in blood pressure and pulse rate. These results suggest that traxanox sodium is a useful diuretic agent with uricosuric effect.

Administration, Oral↗
PubMed1986

Chronopharmacological study of furosemide in rats.

The present experiment was undertaken to determine whether or not the effects of furosemide depend upon the administration time and, if so, to study the mechanism(s) for these variations. After administration of furosemide (5 mg/kg) in Wistar rats at 10:00 or at 22:00, urine volume and urinary excretion of sodium, furosemide, and prostaglandin E2 (PGE2) were measured. Urine volume and urinary excretion of sodium and furosemide, but not PGE2, were significantly greater when furosemide was administered at 10:00 than when it was administered at 22:00. There was a good correlation between the urinary output of furosemide and the urine volume, or the urinary sodium. It is concluded that the effects of furosemide vary with the administration time and these variations depend upon the amount of furosemide secreted in urine.

Animals↗
PubMed1986

Pharmacokinetics and pharmacodynamics of captopril in patients undergoing continuous ambulatory peritoneal dialysis.

Pharmacokinetics and pharmacodynamics of captopril were studied in 5 continuous ambulatory peritoneal dialysis (CAPD) patients (including 2 hypertensive patients) after single oral administration of 50 mg captopril. The pharmacokinetic parameters for plasma free unchanged captopril were time to maximal concentration 1.1 +/- 0.3 h, maximal plasma concentration 387 +/- 75 ng X ml-1, elimination half-life 1.0 +/- 0.3 h, and the area under the concentration-time curve 711 +/- 144 ng X h X ml-1. For plasma total captopril (the sum of free unchanged captopril and its disulfide compounds) the values were time to maximal concentration 3.5 +/- 0.6 h and maximal plasma concentration 2,777 +/- 429 ng X ml-1. Captopril was detected in the dialysis fluid in all CAPD patients. Blood pressures in the 2 hypertensive CAPD patients were lower at 24 h after than before captopril administration. These results suggest that captopril may be eliminated by CAPD. In addition, there is a possibility that the antihypertensive effects of captopril may be prolonged in hypertensive CAPD patients.

Adult↗
PubMed1986

A case of acute renal failure associated with type A acute hepatitis responds dramatically to plasmapheresis.

A case of acute renal failure (ARF) associated with type A acute hepatitis followed by a dramatic response to plasmapheresis is described. A female patient was transferred to our hospital with a diagnosis of ARF associated with acute hepatitis. Since radioimmunoassay for IgM antibody to hepatitis A virus showed a positive reaction, recent infection with hepatitis A virus was suspected. Hemodialysis immediately performed after admission was not effective. Plasmapheresis was started on the 5th hospital day and there was a dramatic improvement in ARF and hepatitis. It is concluded that plasmapheresis is effective in the treatment of ARF associated with liver disease if it is applied in the early stage.

Acute Kidney Injury↗
PubMed1984

Clinical pharmacokinetics and pharmacological actions of a long-acting formulation of propranolol.

The pharmacokinetics and pharmacodynamics of a long-acting formulation of 60 mg propranolol (Inderal LA; in the following briefly called LA) once a day were compared with those of conventional propranolol (Inderal; in the following called CV) 20 mg three times a day, by a double-blind cross-over method in healthy volunteers. After a single oral dose with LA in 10 subjects, the blood level slowly increased to reach the peak plasma level (Cmax) of 11.56 +/- 2.15 ng/ml (mean +/- SE) at 5 h which was lower than that of CV (42.93 +/- 19.26 ng/ml). However, the peak plasma level was almost constant for another 5 h with LA (11.03 +/- 2.38 ng/ml at 10 h). The elimination half-life with LA was significantly longer than with CV (6.5 +/- 1.0, 3.9 +/- 0.5 h, respectively). The plasma level at 24 h did not differ between LA and CV (3.34 +/- 0.92, 5.47 +/- 1.38 ng/ml, respectively). LA and CV were orally administered for 8 consecutive days in 6 subjects. The plasma level after LA accumulated and Cmax was 1.6 times higher and the area under the time-concentration curve (AUC) 1.7 times higher than on Day 1, but no accumulation of the plasma level was seen after CV. On Day 8 the plasma level after 24 h of LA turned-out to be higher than that of CV (4.4 +/- 2.2, 3.5 +/- 1.5 ng/ml). Although the exercise heart rate was significantly more suppressed by CV than LA on Day 1, the difference disappeared on Day 8.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Pharmacokinetics and the antiarrhythmic effect of mexiletine in patients with chronic ventricular arrhythmias.

A new antiarrhythmic agent, 1-(2,6- dimethylphenoxy )-2-aminopropane (mexiletine), was investigated in 10 patients with chronic premature ventricular contractions (PVCs) to evaluate the antiarrhythmic efficacy and the pharmacokinetics after single intravenous, single oral and repeated oral dosings of mexiletine 150 mg. Mexiletine was well absorbed from the intestinal tract. The relative bioavailability was 83.2 +/- 8.9% (mean +/- S.E.). The time-concentration curve of mexiletine fitted in well with two-compartment open model. Elimination half-life, volume of distribution and plasma clearance were 10.54 +/- 0.26 h, 2.10 +/- 0.49 l/kg, 6.01 +/- 0.63 ml/min/kg, respectively. The computer-simulated time-concentration curves of multiple oral dosings , which were based on the kinetic parameters from single oral dosing, conformed well with measured concentrations. This might be applied to predict the plasma level of mexiletine. The steady state of plasma mexiletine level was reached 4-5 days after 450 mg/day dosings and ranged 0.75-2.18 micrograms/ml. In 6 of 10 patients, the frequency of PVCs was suppressed more than 75% as compared with the pre-medication value. Mexiletine was well tolerated at a dose of 450 mg/day. However, of 4 patients with the dose increased to 600 mg/day, the administration was ceased in three patients due to gastrointestinal symptoms and tremor. All of these adverse reactions disappeared when the administration was stopped. These results suggest that mexiletine is effective against ventricular arrhythmias and the dosage should be carefully adjusted. The prediction of plasma level would be applied to the dosage regimen of mexiletine.

Adult↗
PubMed1983

Effects of intracerebroventricular administration of prostaglandin D2 and angiotensin II on blood pressure in conscious rats.

To evaluate the role of brain prostaglandins in the regulation of blood pressure, we examined the effects of intracerebroventricular injections of prostaglandin D2, angiotensin II and indomethacin on blood pressure in conscious rats. Intraventricular administration of prostaglandin D2, the major prostaglandin synthesized in the rat brain, did not elicit a significant change in blood pressure. On the other hand, intraventricular injection of angiotensin II resulted in an increase in blood pressure in a dose-related manner. However, this central pressor effect of angiotensin II was not affected by intraventricular pretreatment with indomethacin. Indomethacin per se did not induce any change in blood pressure. These results suggest that prostaglandin D2 in the brain does not play an important role in the regulation of blood pressure in conscious rats. It is also suggested that the central pressor effect of angiotensin II is not mediated by prostaglandin biosynthesis in the central nervous system.

Angiotensin II↗
PubMed1983

Pharmacodynamic and pharmacokinetic study of a slow-release formulation of furosemide in man.

A slow-release formulation of 40 mg furosemide as capsules (Eutensin) was investigated for its pharmacokinetic and pharmacodynamic properties in comparison with conventional tablets containing 40 mg furosemide (Lasix) in a single-blind clinical pharmacological trial in 6 healthy subjects. The following results were obtained: 1. The AUC0-24 after the administration of slow-release (SR) furosemide was about 42% of that after furosemide tablets. 2. Urine volume and urinary excretion of Na and Cl were significantly greater after furosemide tablets than after SR furosemide during the first 10 h after administration. No significant difference was observed between the two formulations in the urinary excretion of K, creatinine and uric acid. No significant difference was noted in every tested pharmacodynamic parameter during the cumulative 24 h after administration. It was concluded that SR furosemide may be used in the treatment of hypertension due to its characteristics of a slow-release diuretic feature, delayed peak blood concentration, delayed maximum diuretic effect and prolonged duration of action.

Adult↗
PubMed1982

Clinical pharmacology of a new beta-adrenoceptor blocking drug, befunolol. Cross-over comparison with propranolol on repeated administration.

Repeated doses of a new beta-adrenoceptor blocking agent, befunolol, were administered orally to adult male volunteers for a cross-over comparison with propranolol. The beta-adrenoceptor blocking activity of befunolol was greater than that of propranolol when assessed by the percentage reduction in exercise-induced tachycardia. The elimination half-life of drug was significantly prolonged on repeated administration of propranolol, but not of befunolol. The percentage reduction in exercise-induced tachycardia was highly correlated with the log plasma level of each drug. Both drugs produced a significant reduction in pre-exercise systolic and diastolic blood pressure, and significant attenuation of exercise-induced rise in systolic blood pressure.

Adrenergic beta-Antagonists↗
PubMed1982

Eicosapolyenoic acids of serum lipids of Japanese islanders with low incidence of cardiovascular diseases.

Japanese are unique among the peoples of developed countries in having a high intake of eicosapentaenoic acid (C 20:5) from fresh fish and this may in part contribute to their low incidence of cardiovascular diseases. Mass spectroscopic analyses of eicosapolyenoic acids (C20:3, C20:4 and C20:5) were carried out on the serum of aged persons living on Kohama island in Okinawa and known to have the lowest incidence of cardiovascular diseases in Japan. All but 4 of the 77 persons examined (73.94 +/- 7.81 years old) led active fishing-farming lives. The total amount of eicosapolyenoic acids in the serum of persons on Kohama island (46.77 +/- 7.46 mg/100 ml) was higher (p less than 0.001) than that in people on mainland Japan, owing to the higher intake of fresh fish (147.7 g/day). A positive correlation (p less than 0.01) was found between serum C 20:5 concentration (6.82 +/- 2.54 mg/100 ml) and high density lipoprotein concentration (55.38 +/- 13.83 mg/100 ml). In addition, there were positive correlations (p less than 0.01) between serum C 20:3 concentration (6.58 +/- 1.61 mg/100 ml) and total cholesterol (188.60 +/- 32.30 mg/100 ml), and triglyceride and skinfold thickness. The blood pressure level (p less than 0.01), incidence of abnormal ECG (p less than 0.05), and salt intake (6.2-8.3 g/day) estimated from urinalysis, were all lower than the average figures for Japanese of similar ages. No persons examined showed Q-wave on ECG. The percentage of smokers and drinkers were similar for Kohama island and mainland Japan.

Activities of Daily Living↗
PubMed1982

Hypotensive effect of nifedipine in hypertensive patients with chronic renal failure.

The hypotensive effect of 4-(2'-nitrophenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxydimethylester (nifedipine, Adalat) was studied in 15 hypertensive patients with chronic renal failure. The decrease of blood pressure lasted for approximately 3 h and maximum decrement was achieved in 1 h after oral administration of nifedipine (10 mg). Hypotensive action of the drug was associated with a constant decrease in total peripheral resistance and an increase in cardiac output, plasma renin activity (PRA), and plasma norepinephrine (noradrenaline). Initial PRA was apparently the major determinant of the rise in PRA since a close correlation was present between the initial value and the increase induced by nifedipine (r = 0.93, p less than 0.05). Marked reduction of blood pressure without noticeable side effects was observed in two cases who had not responded to previous antihypertensive treatment. These data suggest that nifedipine exerts its hypotensive action through peripheral vasodilation and may be an effective drug for treatment of hypertension during chronic renal failure.

Adolescent↗
PubMed1981

Pharmacokinetics and pharmacodynamics of propranolol stereoisomers in hyperthyroid patients.

The disposition of propranolol stereoisomers after administration of a single oral dose of the racemic drug was investigated in seven hyperthyroid patients before and after antithyroid drug therapy. The possibility of hypersensitivity to propranolol in the patients was evaluated by constructing plasma propranolol concentration -- beta-blocking effect curves. There was no statistically significant difference in elimination half-life (t1/2) between (+/-)- and (-)-propranolol before and after antithyroid drug therapy. However, the plasma clearance (Vp) of (-)-propranolol was smaller than that of (+/-)-propranolol, and the difference was statistically significant after antithyroid drug therapy. Vp decreased or did not change in young patients after therapy. No significant difference was observed in the relationship between the tilt-induced pulse rate response and plasma propranolol concentration when treated patients became euthyroid compared to their response in the hyperthyroid state.

Adult↗
PubMed1981

Role of dopamine in the regulation of blood pressure and the renin--angiotensin--aldosterone system in conscious rats.

1. In conscious rats, intracerebroventricular injection of dopamine resulted in a decrease in blood pressure, whereas injection of metoclopramide, the dopamine antagonist, produced an increase in blood pressure. The central depressor effect of dopamine was attenuated by a subpressor pretreatment with intraventricular metoclopramide, but not by phentolamine. 2. Intravenous administration of dopamine increase blood pressure. This increase in blood pressure was almost completely abolished by intravenous phentolamine. Metoclopramide, when injected intravenously, did not reduce any change in blood pressure. 3. Plasma renin activity and plasma aldosterone concentration were decreased by intraventricular injection of dopamine, and increased by that of metoclopramide. In contrast, intravenous administration of metoclopramide increased plasma aldosterone concentration without changing plasma renin activity. Plasma concentrations of potassium, sodium and corticosterone were not affected by these treatments. 4. These results suggest that the dopaminergic system in the brain, but not in the systemic circulation, is involved in the regulation of blood pressure. It is also suggested that the central dopaminergic system participates in the regulation of aldosterone secretion by changes in the renin--angiotensin axis, whereas the peripheral dopaminergic modulation of aldosterone secretion appears to occur independently of the renin--angiotensin system.

Aldosterone↗